Method and system for planning the path of an agricultural vehicle

ABSTRACT

A method and system for planning a path for an agricultural vehicle is disclosed. The agricultural vehicle includes a steering mechanism configured to automatically steer the agricultural vehicle. The method includes accessing a recorded path plan, the recorded path plan including navigation data recorded during a previous path passage of the agricultural vehicle through a work area using a position determining system. The method also includes determining a first point on a first planned path accessed from the recorded path plan, determining a second point on a second planned path accessed from the recorded path plan, generating a connection path plan connecting the first point and the second point, generating a steering command based on the connection path plan, and providing the steering command to the steering mechanism to cause the agricultural vehicle to travel according to the connection path plan.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/363,839, filed Feb. 27, 2006, titled METHOD AND SYSTEM FOR PLANNINGTHE PATH OF AN AGRICULTURAL VEHICLE, the disclosure of which is herebyincorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

The present invention relates to planning the path of an agriculturalvehicle. However, the invention is not limited to use in agriculture,but includes such other applications as may be apparent to one skilledin the art.

BACKGROUND

Operating agricultural vehicle such as tractors and harvesters oftenrequires highly repetitive operations. Due to the repetitive nature ofthe work, and irregularities in the terrain, gaps and overlaps in therows of crops can occur. This can result in damaged crops, overplanting,or reduced yield per acre. Additionally, it is often desirable for avehicle to follow a set path pattern over an area, for example whenplanting a field, conducting a search, or to reproduce a previouslycreated path pattern at a later date. For example, a field may beploughed, then sowed or planted, fertilized, sprayed and harvested.Following the same path pattern over the field each time ensures thateach subsequent action is targeted to the correct area. It is thereforeadvantageous to pre-plan the paths that a vehicle will follow. As thesize of agricultural vehicles and fanning implements continues toincrease, precisely controlling their motion becomes more important.

Guidance systems are increasingly used for controlling agricultural andenvironmental management equipment and operations such as road sidespraying, road salting, and snow plowing where following a previouslydefined route is desirable. This allows more precise control of thevehicles than is typically realized than if the vehicle is steered by ahuman.

Projected paths may be used to guide a vehicle directly, or transmittedto an onboard display to be followed by a human operator. Systems ofcourse-correction may be used to minimize cross-track and offset if thevehicle deviates from a pre-projected path. Gain tuning may also beapplied to the auto-steering system in order to approximate thedifferences in human steering when the vehicle is traveling at differentspeeds.

There exist current systems for pre-planning the path of a vehicle.However, the produced set of paths are often disjointed. Typically, atthe end of each path, a driver must disengage the auto-drive, manuallydirect the vehicle to the next path to be driven and line up the vehiclewith the new path.

Known methods of steering an agricultural vehicle may include selectinga desired position and heading and calculating a desired radius ofcurvature to arrive at the desired track with a desired heading. Thissystem is real time feedback system, which takes into account thecontours of the surface and continually corrects the course of thevehicle.

Another method is to use a vision based system of automated vehiclesteering. An electromagnetic sensor is used to gather information aboutfield characteristics, and plan a trajectory. This includes determiningpoints in the path matrix the vehicle will be guided towards anddetermining the desired wheel angle required such that the vehicleorigin will pass through that point, given the vehicle's positionrelative to that point and the turning radius.

It is also known to pre-determine entrance points and advance points ona pre-planned path, but the means of planning an appropriate pathbetween points on a pre-planned path or set of paths has not beendiscussed.

DISCLOSURE OF THE INVENTION

Embodiments of the present invention pertain to methods and systems forplanning the path of an agricultural vehicle. In one embodiment, a firstpoint of a first planned path and a second point of a second plannedpath are determined. A path plan is then automatically generatedconnecting the first point and the second point.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the present invention and,together with the description, serve to explain the principles of theinvention. Unless specifically noted, the drawings referred to in thisdescription should be understood as not being drawn to scale.

FIGS. 1A and 1B show an exemplary vehicle control system in accordancewith embodiments of the present invention.

FIG. 2A is a block diagram of an exemplary guidance system in accordancewith embodiments of the present invention.

FIG. 2B is a block diagram of an exemplary control component inaccordance with embodiments of the present invention.

FIG. 3 is a flow chart showing one implementation of a method ofdetermining the path of a mobile machine in accordance with embodimentsof the present invention.

FIG. 4 shows a work area and a plurality of paths plotted in accordancewith embodiments of the present invention.

FIG. 5 shows another work area and a plurality of paths plotted inaccordance with embodiments of the present invention.

FIG. 6 is a flowchart of a method for planning the path of anagricultural vehicle in accordance with embodiments of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. While the present invention will be described in conjunctionwith the following embodiments, it will be understood that they are notintended to limit the present invention to these embodiments alone. Onthe contrary, the present invention is intended to cover alternatives,modifications, and equivalents which may be included within the spiritand scope of the present invention as defined by the appended claims.Furthermore, in the following detailed description of the presentinvention, numerous specific details are set forth in order to provide athorough understanding of the present invention. However, embodiments ofthe present invention may be practiced without these specific details.In other instances, well-known methods, procedures, components, andcircuits have not been described in detail so as not to unnecessarilyobscure aspects of the present invention.

Notation and Nomenclature

Some portions of the detailed descriptions which follow are presented interms of procedures, logic blocks, processing and other symbolicrepresentations of operations on data bits within a computer memory.These descriptions and representations are the means used by thoseskilled in the data processing arts to most effectively convey thesubstance of their work to others skilled in the art. In the presentapplication, a procedure, logic block, process, or the like, isconceived to be a self-consistent sequence of steps or instructionsleading to a desired result. The steps are those requiring physicalmanipulations of physical quantities. Usually, although not necessarily,these quantities take the form of electrical or magnetic signal capableof being stored, transferred, combined, compared, and otherwisemanipulated in a computer system.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the followingdiscussions, it is appreciated that throughout the present invention,discussions utilizing terms such as “determining,” “amending,”“utilizing,” “generating” or the like, refer to the action and processesof a computer system or similar electronic computing device, thatmanipulates and transforms data represented as physical (electronic)quantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

FIG. 1A illustrates a block diagram of a vehicle control system 100 inaccordance with an embodiment of the present invention. In embodimentsof the present invention, the vehicle control system 100 may beimplemented as an integrated guidance system that can be mounted on thedashboard, windshield, or ceiling of a vehicle such as, a tractor. Inone embodiment, vehicle control system 100 is integrated with a steeringcomponent (e.g., 230 of FIG. 2A) which may be coupled with the steeringcolumn or steering shaft of the mobile machine (e.g., 105 of FIG. 1B)being controlled and is operable for actuating the steering mechanismthereof. In other embodiments of the present invention, vehicle controlsystem 100 may be implemented as a plurality of discrete componentswhich are communicatively coupled in a network.

In accordance with embodiments of the present invention, vehicle controlsystem 100 determines the geographic position of a vehicle or othermobile machine and determines whether the vehicle is traveling in adesired direction. Additionally, if the vehicle is not traveling in adesired direction, vehicle control system 100 determines a coursecorrection for the vehicle and generates a steering command to implementthe course correction. For the purposes of the present invention, theterm “geographic position” means the determining in at least twodimensions (e.g., latitude and longitude), the location of a mobilemachine (e.g., 105). Furthermore, for purposes of the present invention,the term “course correction” means a change in the direction traveled bythe vehicle such that it is guided from a current direction of travel toa desired direction of travel.

Embodiments of the present invention facilitate controlling the steeringof mobile machines, thus allowing more precise control of the machinethan may be realized by a human operator under certain conditions. Forexample, a snowplow may operate under conditions in which a humanoperator's ability to see the road is diminished. Additionally, whenperforming highly repetitive tasks such as plowing a field, embodimentsof the present invention facilitate controlling the vehicle moreprecisely, thus minimizing errors in controlling the vehicle which mayresult in gaps or overlaps in the field. Embodiments of the presentinvention are also well suited for reproducing a previously created pathpattern at a later date. Furthermore, embodiments of the presentinvention are well suited for planning and guiding the path of themobile machine such that sharp turns are eliminated from the plannedpath of the mobile machine in a reliable and repeatable manner.

Again, it should be understood that vehicle control system 100 of thepresent invention can be utilized with a variety of mechanical systemsthat are capable of movement. Although the present discussion will focuson guidance of vehicles such as, for example, agricultural vehicles andequipment, the invention is not limited to the guidance and use onagricultural vehicles alone.

Referring again to FIG. 1A, the vehicle control system 100 includes aposition determining system (PDS) 110, a guidance system 120, and amedia access device 130 which are coupled via a bus 115. Additionally, aterrain compensation module (TCM) 140, an optional data storage device150, and a user interface 160 are coupled with bus 115. Also, anoptional display 170, an optional communication device 180, and anoptional position correction system 190 are coupled with bus 115. In theembodiment of FIG. 1A, these components are disposed within a housing109. Input/output (I/O) port 45 and connector 55 facilitatecommunicatively coupling vehicle control system 100 with othercomponents such as the steering component described above (e.g. 230 ofFIG. 2A). While the present embodiment shows these components disposedwithin housing 109, embodiments of the present invention are well suitedto various combinations of these components. For example, in oneembodiment, position determining system 110 and terrain compensationmodule 140 may be disposed within a housing (not shown) of antenna 107.In other embodiments of the present invention, vehicle control system100 may be implemented as a plurality of discreet components which arecommunicatively coupled in a network devices.

In one embodiment of the present invention, position determining system110 is a satellite based position determining system and receivesnavigation data from satellites via antenna 107. Examples of satellitebased position determining systems include the global positioning system(GPS) navigation system, a differential GPS system, a real-timekinematics (RTK) system, a networked RTK system, etc. While the presentembodiment recites these position determining systems specifically, itis appreciated that embodiments of the present invention are well suitedfor using other position determining systems as well such asground-based position determining systems, or other satellite-basedposition determining systems such as the GLONASS system, the GlobalNavigation Satellite System (GNSS), the Radionavigation SatelliteService (RNSS), or the Galileo system currently under development.

In the embodiment of FIG. 1A, position determining system 110 utilizes aprocess of triangulation from several satellites, which are transmittingposition determination signals, to determine the current position of thevehicle. The position determining system 110 is coupled with antenna 107via a coupling 108. As shown in FIG. 1A, antenna 107 is disposed outsideof housing 109 to facilitate mounting antenna 107 outside of the vehicle(e.g., mounted on the hood or roof of mobile machine 105) if, forexample, the received GPS signals from the GPS satellites are not bestrong enough inside the vehicle. However, in embodiments of the presentinvention, antenna 107 may also be disposed within housing 109. Itshould be understood that the position determining system 110 can beimplemented to utilize position determination signals from othersatellite-based systems, land-based systems, or hybrid (satellite-land)systems as well.

The accuracy of the current position of the vehicle determined by theposition determining system 110 depends on factors such as time of theday, number of GPS satellites available, atmospheric conditions,accuracy of the components, etc. These factors can introduce errors inthe determination of the current position of the vehicle.

A process known as differential correction can correct many of theseerrors. Differential GPS is an enhanced form of GPS. Differential GPSpositions are more accurate than regular GPS positions. Differential GPSpositions are regular GPS positions that have been corrected foratmospheric conditions and/or other errors using the process ofdifferential correction. Typically, differential correction uses a GPSreference station, such as a GPS station that has a well-known location,to provide corrections for other GPS receivers that are at unknownlocations (such as on a vehicle). Differential corrections may beapplied second-by-second in real time. These are known as real-timedifferential corrections. Alternatively, differential corrections mayalso be stored in electronic files (e.g., in data storage device 150)and accessed later.

There are many sources of differential corrections. These sourcesinclude a short-range radio link from a local GPS reference station, amedium-range radio link from maritime or land-based beacons, andgeo-stationary satellites. Geo-stationary satellites use multipleland-based reference stations to create a differential correction mapover very large areas of the earth. One of these systems is the WideArea Augmentation System (WAAS).

In an embodiment of the present invention, differential correctioncapability is integrated into the position determining system 110 ofFIG. 1A. In the embodiment shown in FIG. 1A, the optional positioncorrection system 190 provides the differential correction capability.As described above in an embodiment of the present invention, theposition determining system 110 utilizes satellites of the GlobalPositioning System. Thus, the position correction system 190 includes aDifferential Global Positioning System (DGPS) receiver 192 forcorrecting errors in the GPS position using GPS differentialcorrections, a DGPS antenna 191 for receiving GPS differentialcorrection signals. In embodiments of the present invention, DGPSantenna 191 and DGPS receiver 192 may be coupled via a cable tofacilitate positioning DGPS antenna 191 outside of the vehicle or, asshown in FIG. 1A, disposed within housing 109.

As will be discussed in greater detail below, guidance system 120 usesposition data from position determining system 110, user input (e.g., adesired pattern or direction), as well as vector data such as desireddirection and distance to determine course corrections which are usedfor guiding mobile machine 105. Furthermore, guidance system 120 isfurther for reproducing a previously created path pattern at a latertime and for planning a path for mobile machine 105 that is contiguous,and which is both repeatable and reliable.

In embodiments of the present invention, media access device 130facilitates accessing data from removable media storage devices.Examples of removable media storage devices accessible in accordancewith embodiments of the present invention include, but are not limitedto, floppy disks, optical media storage devices (e,g., compact disks(CDs) and digital versatile disks (DVDs), and flash memory devices suchas Secure Digital Input/Output (SDIO) cards, CompactFlash memorydevices, MultiMediaCard memory devices, SmartMedia memory devices, orother integrated circuit memory devices. More generally, media accessdevice 130 is for accessing digital data stored on a removable mediastorage device.

TCM 140 provides the ability to compensate for terrain variations whichcan reduce the precision of position determining system 110 indetermining the geographic position of a vehicle. For example, whentraversing a hillside, the antenna 107 can be displaced to one side orthe other with respect to the centre line of mobile machine 105, thuscausing errors in determining its geographic position. As a result, gapsor overlaps can occur when plowing across contoured terrain is beingperformed. TCM 140 can detect the magnitude of displacement of antenna107 with respect to the centre line of mobile machine 105 (e.g., due toroll, pitch, and yaw) and send signals which allow guidance system 120to generate steering commands which compensate for the errors indetermining the geographic position. In embodiments of the presentinvention, TCM 140 may utilize gyroscopes, accelerometers, tilt sensors,rotation sensors, and the like to determine the displacement of antenna107 from a first position to a second position with respect to thecenterline of mobile machine 105.

Because vehicle control system 100 may be coupled with a vehicle using,for example, suction cups, it may be beneficial to calibrate TCM 140prior to operating system 100. For example, if vehicle control system100 is tilted when the system is started up, a bias may be induced whichprevents TCM 140 from accurately determining the offset of antenna 107from the centerline of the vehicle. In one embodiment, a circular levelmay be fixedly mounted in the vehicle in a location which can be seen bythe vehicle operator. The vehicle can be parked at a level area and thecircular level adjusted to indicate that the vehicle is level. Themounting hardware for the circular level can then be tightened toprevent the circular level from being tilted. A second circular levelcan be mounted on vehicle control system 100. When the circular level inthe vehicle shows that the vehicle is parked in a level area, a user canmanually change the mounting angle of vehicle control system 100 so thatthe circular level mounted thereupon indicates that the integratedguidance system is also level.

In another embodiment, the levels indicate the magnitude of the tilt ofthe vehicle of the vehicle control system 100. When the level mounted inthe vehicle indicates, for example, a tilt of five degrees to the left,the vehicle operator can tilt integrated guidance system five degrees tothe left as well. As a result, both the vehicle and vehicle controlsystem 100 are tilted in a similar direction and magnitude.

In another embodiment, an electronic auto-level (not shown) may becoupled or built into vehicle control system 100 which automaticallyremoves bias induced by the mounting angle of vehicle control system100. To check whether tilt-induced bias has been removed, an operatorcan drive the vehicle over the same ground in opposite directions. Ifthere is no tilt-induced bias, the wheels of the vehicle shouldsubstantially traverse the same wheel tracks as in the previous pass. Ifthere is a mis-alignment of vehicle control system 100 due to tilt,antenna 107 will not be in the expected position. As a result, thevehicle will follow different paths when successive passes are madeacross the same ground.

In embodiments of the present invention, optional data storage device150 may comprise a volatile memory random access memory (RAM) forstoring the digital information and instructions, or non-volatile datastorage device such as a hard disk drive, flash memory or other opticalor magnetic storage device. Data storage device 150 can be used to storedigital information and instructions such as the curve smoothing methodof the present invention. It should be noted that the software programfor implementing the path planning method of the present invention canalso be stored in removable media storage devices accessible by mediaaccess device 130. In embodiments of the present invention, data storagedevice 150 may be remotely located from vehicle control system 100. Forexample, communication device 180 may be a radio transceiver or cellulartelephone device which can wirelessly transmit data from vehicle controlsystem 100 to a remotely located data storage device 150 (e.g., via theInternet).

In embodiments of the present invention, data storage device 150 mayalso be used to log or record information such as field boundaries, roadpathways, or where the vehicle has previously gone. This last functionis particularly useful because records must be kept regarding theapplication of chemicals or fertilizers to, for example, farm fields inorder to comply with environmental regulations. Embodiments of thepresent invention facilitate logging this information for laterretrieval.

In embodiments of the present invention, the user interface 160 isadapted for enabling an operator to access and interact with any one ofthe available functions of the vehicle control system 100 with a minimumnumber of inputs and with minimum use of the inputs. An “input” refersto a button, key, switch or any other electronic or mechanical means fora user to communicate information such as, for example, data, a command,a selection or a choice, to an electronic device. In an embodiment, theuser interface 160 may comprise a plurality of buttons. In anotherembodiment, user interface 160 may comprise an alpha-numeric keypadand/or a device for controlling a cursor displayed upon display device170. Examples of cursor control devices include, but are not limited to,a trackball, mouse, touch pad, joystick, or special keys on thealpha-numeric keypad. In other embodiments, a voice recognition system(not shown) may be used to facilitate input of commands withoutrequiring a user to operate user interface with his/her hands.

In embodiments of the present invention, user interface 160 isconveniently positioned and integrated with respect to housing 109 foreasy access by an operator. As a result, an operator can use withoutdifficulty the vehicle control system 100 while operating the vehicle,since distractions (e.g., too many inputs to select, position of theinputs is not convenient, need for visual assistance to distinguishinputs. etc.) originating from using the user interface by otherguidance systems are significantly reduced.

In embodiments of the present invention, display 170 comprises a displaydevice for displaying text and graphics. In an embodiment, the displaydevice 170 may be, but is not limited to, a liquid crystal display(LCD). In another embodiment, display 170 may comprise a touch paneldisplay (e.g., using resistive, capacitive, inductive, or pressuresensitive input detection) to facilitate input of data such as usertouch screen commands. The display device 170 can be implemented withother display technologies. Moreover, the display device 170 is compactto minimize obstructing the vision of the operator and to reduce thesize of the vehicle control system 100.

In embodiments of the present invention, display device 170 may generatea lightbar display that is adapted for providing a visual representationof a deviation of the current position of the vehicle from a desiredpath to guide an operator in controlling movement of the vehicle alongthe desired path. Typically, the lightbar comprises a light pattern thatindicates the deviation of the vehicle from the desired path. It shouldbe understood that in embodiments of the present invention, the lightbarmay be implemented as a plurality of discreet light emitting elementsthat are separate from display device 170.

In embodiments of the present invention, vehicle control system 100 canbe coupled with steering component 230 via the I/O port 45. Moreover,vehicle control system 100 can have one or more I/O ports 45, thusfacilitating the downloading and uploading of data. In an embodiment,the I/O port 45 is a serial port which is compliant with, but notlimited to, the controller area network (CAN) protocol. CAN is a serialbus system which was developed for automotive use in the early 1980s.The Society of Automotive Engineers (SAE) has developed a standard CANprotocol, SAE J1939, based upon CAN specification 2.0. The SAE J1939specification provides plug-and-play capabilities and allows componentsfrom various suppliers to be easily integrated in an open architecture.It is noted that in embodiments of the present invention, discreetcomponents of vehicle control system 100 may be communicatively coupledusing a CAN bus. For example, position determining system 110, guidancesystem 120, and steering component 230 may be communicatively coupledusing a CAN bus in embodiments of the present invention. It isappreciated that other discreet components of vehicle control system 100may also be coupled using the CAN bus as well.

In the embodiment of FIG. 1A, connector 55 is for conveying electricalpower from mobile machine 105 to vehicle control system 100. However, itis appreciated that in another embodiment, vehicle control system may bepowered by internal batteries (not shown).

FIG. 2A is a block diagram of an exemplary guidance system 120 inaccordance with embodiments of the present invention. In the embodimentof FIG. 2A, guidance system 120 comprises a control component 210 whichis coupled with an optional steering controller 220. It is appreciatedthat in embodiments of the present invention, control component 210 maybe implemented as a single unit separate from steering controller 220,or as an integrated unit as shown in FIG. 2A.

In embodiments of the present invention, control component 210 accessesposition data from position determining system 110, user input such as adesired pattern or direction, as well as vector data such as desireddirection and distance to determine course corrections which are usedfor guiding mobile machine 105. In embodiments of the present invention,roll, pitch, and yaw data from TCM 140 may also be used to determinecourse corrections for mobile machine 105. In embodiments of the presentinvention, guidance system 120 is a commercially available guidancesystem such as, for example, the AgGPS® guidance system, or theEZ-Guide® system, both of which are manufactured by Trimble NavigationLtd. of Sunnyvale Calif.

Additional data used to determine course corrections may also compriseswath calculation which takes into account the width of variousimplements which may be coupled with mobile machine 105. For example, ifa harvester can clear a swath of 15 feet in each pass, control component210 may generate commands which cause mobile machine 105 to follow apath 15 feet to one side of the preceding swath in the next pass.Control component 210 may also be programmed to follow straight orcurved paths which is useful when operating in irregularly shaped orcontoured fields or in fields disposed around a centre pivot. This isalso useful in situations in which the path being followed by mobilemachine 105 is obscured. For example, an operator of a snowplow may notbe able to see the road being cleared due to the accumulation of snow onthe road. Additionally, visibility may be obscured by dust, snow, rain,or fog. Thus, it would be advantageous to utilize embodiments of thepresent invention to guide mobile machine 105 in these conditions.

In embodiments of the present invention, the course correctioncalculated by control component 210 is sent from control component 210to steering controller 220. Steering controller 220 translates thecourse correction generated by control component 210 into a steeringcommand for manipulating the steering mechanism of mobile machine 105.Steering controller 220 generates a message conveying the steeringcommand to steering component 230. In embodiments of the presentinvention, the communicative coupling between control component 210,steering controller 220 and steering component 230 is accomplished usingcoupling I/O port 42 (e.g., a serial bus, or CAN bus).

In embodiments of the present invention, steering component 230 maycomprise an electric steering component 231, or a hydraulic steeringcomponent 232. Thus, as shown in FIG. 2A, steering controller 220comprises a first output 221 for coupling steering controller 220 withelectric steering component 231, and a second output 222 for couplingsteering controller 220 with hydraulic steering component 232. Becausecoupling 115 may be compliant with the CAN protocol, plug and playfunctionality is facilitated in guidance system 120. Therefore, inembodiments of the present invention, steering controller can determinewhich steering component it is coupled with depending upon which outputof steering controller 220 is used.

Steering controller 220 then generates a message, based upon thesteering component with which it is coupled, which causes the steeringcomponent to actuate the steering mechanism of mobile machine 105. Forexample, if steering controller 220 determines that output 221 is beingused, it generates a steering command which is formatted for controllingelectric steering component 231. If steering controller 220 determinesthat output 222 is being used, it generates a steering command which isformatted for controlling hydraulic steering component 232.

FIG. 2B is a block diagram of an exemplary control component 210 inaccordance with embodiments of the present invention. In FIG. 2B,control component 210 comprises an input 211 which is coupled with anaccessor 212, a path plan generator 213, and a course correctiongenerator 214 via a bus 219. A display output 215 and a communicationinterface 216 are also coupled with bus 219. In embodiments of thepresent invention, input 211 is communicatively coupled with bus 115 ofFIG. 1A. Thus, control component 210 may directly access geographicposition data generated by position determining component 110 via input211.

In embodiments of the present invention, a plurality of planned pathsare accessed via input 211 by accessor 212. It is noted that the plannedpath accessed by control component 210 may be input into system 100 by auser, or previously stored data accessed via data storage device 150,media access device 130, or transmitted via communication device 180.Path plan generator 213 then assigns a sequence to the plurality ofplanned paths. Again, this may be in response to user input, orperformed automatically by path plan generator in embodiments of thepresent invention. A first point lying on a first planned path isdetermined and a second point lying on the next planned path, or secondplanned path, in the sequence. In embodiments of the present invention,path plan generator 213 then automatically calculates a path plan whichconnects a point of the first planned path with a point of a secondplanned path of the plurality of planned paths. In a preferredembodiment system 100 is adapted to plan turns between planned swathpaths for an agricultural field. More specifically, path plan generator213 determines the geographic position of the end point of the firstplanned path, the geographic position of the start point of the secondplanned path, and generates a path plan which connects those two points.

In embodiments of the present invention, path plan generator 213 mayselect a shape for the generated path plan from a plurality ofpre-planned path plan shapes. This may be performed automatically bypath plan generator 213 or in response to a user selection. Inembodiments of the present invention path plan shapes which may beselected by path plan generator 213 may comprise, but are not limitedto, a semicircle (e.g., 508 of FIG. 5) and a keyhole shape (e.g., 408 ofFIG. 4). Additionally, path plan generator 213 may access other datawhen selecting a path plan shape. For example, path plan generator mayaccess swath data and data indicating the turning radius of mobilemachine 105, including towed implements coupled thereto, when selectinga path plan. Thus, if the turning radius of mobile machine 105 would beexceeded by selecting a semi-circular path plan between successiveplanned paths, path plan generator 213 may instead automatically selecta keyhole shaped path plan. In embodiments of the present invention,this may override a user selected path plan if safe operating parametersof mobile machine 105 are to be exceeded.

In embodiments of the present invention, upon generating a path plan formobile machine 105, course correction generator 214 may generate acourse correction which is conveyed to steering controller 220 viacommunication interface 216. As described above, embodiments of thepresent invention may be utilized for causing mobile machine 105 toautomatically follow the path plan. Steering controller 220 thengenerates signals or messages to steering component 230 which actuatethe steering mechanism of mobile machine 105 and cause it toautomatically follow the path plan generated by path plan generator 213.In embodiments of the present invention, control component 210 mayaccess position data via position determining system 110 to determinewhether mobile machine 105 is or is not deviating from the path plangenerated by path plan generator 213.

In another embodiment, mobile machine 105 may not be equipped withautomatic steering control equipment (e.g., steering controller 220 andsteering component 230). Thus, in embodiments of the present invention,a visual indication may be sent from control component 210 via displayoutput 215 to display 170 of FIG. 1A. As described above, display 170may provide an operator with a visual indication of a deviation ofmobile machine 105 from a desired direction. In embodiments of thepresent invention, a lightbar may indicate the direction of deviationfrom the planned path generated by path plan generator 213, or be usedto indicate which direction to steer toward in order to again be drivingon the planned path. In another embodiment, this information may bedisplayed on a display screen (e.g., a liquid crystal display device ofdisplay 170). It is noted that the function of components describedabove may be combined in a single functional module such as a dedicatedprocessor of control component 210.

The path plan determined by embodiments of the present invention may bestored for later use. Thus, embodiments of the present inventionfacilitate reliable reproduction of previously created routes and pathswhich can be used as navigation aids for operators of mobile machine105.

In embodiments of the present invention, vehicle guidance system 120 maycomprise control component 210 alone. Thus, in one embodiment, steeringcues may be displayed to an operator of mobile machine 105. For example,a lightbar display (e.g., 170 of FIG. 1A) may provide a visualrepresentation of a deviation of the current position of mobile machine105 from a desired direction. Using this information, the operator canthen affect a course correction for mobile machine 105 to reduce thedeviation from the desired direction.

In another embodiment, guidance system 120 further comprises steeringcontroller 220 which is operable for generating signals that control thesteering mechanism of mobile machine 105. Based upon steering commandsgenerated by control component 210, steering controller 220 generatessignals that actuate the steering mechanism of mobile machine 105 toimplement course corrections automatically.

Referring to FIG. 3, at step 301 a series of planned paths are accessedby system 100. As described above, in embodiments of the presentinvention the paths may comprise digitally created or stored geographicdata. These paths may be paths that have been recorded on previouspasses of the vehicle using the navigation device, manually estimatedpaths or paths generated using a path planning system. Ideally thesystem is integrated into a known path planning system, which generatesthe paths, and then proceeds with the additional steps of the invention(i.e. the projected paths are “auto-input”). In another embodiment, auser may manually input the series of planned paths using, for example,user interface 160.

At step 302 the sequence in which the paths are to be driven isassigned. This may be a sequential order from left to right, a“race-course” pattern following alternate paths from left to right, thenreturning from right to left by the paths previously missed, or anyother pattern selected by the user. In embodiments of the presentinvention, the sequence of planned paths may be assigned by path plangenerator 213. For example, when accessing previously stored data, pathplan generator 213 may not require that the user manually selects thesequence in which the paths are to be driven. In another embodiment, thesequence may be input by a user of system 100.

At step 303 a desired turn path shape for the vehicle to follow betweenpaths is selected. As a default setting, the system may automaticallyselect one desired turn path shape, e.g. a keyhole shape. However, theuser may have the option to manually select a desired turn shape, whichmay be, for example, an arc of a circle or part of another conicsection, a “keyhole” shape, or a combination of curves. Additionally,the desired shape may also be selected based upon the distance betweenthe successive paths to be driven by mobile machine 105 and/or theturning radius of mobile machine 105.

At step 304 a first point, which lies on a first planned path, isdetermined. This is the point at which the turn will commence. The firstpoint may be set in advance by a user, or may be entered in real time asthe vehicle moves down the first planned path by pressing a “turn now”button. In another embodiment, path plan generator 213 may automaticallydetermine the point at which the turn will commence. For example, whenaccessing previously recorded vehicle passes, path plan generator 213may not require that the operator manually sets the first point.

At step 305 the system determines the location of a second point whichlies on a second planned path (the next planned path in the order).Preferably this is the point on the second planned path which is closestto the first point. Again, in embodiments of the present invention, pathplan generator 213 does not require that an operator manually sets thesecond point when, for example, accessing previously stored data.

At step 306, the system calculates a desired turn path shape whichpasses through both the first point and the second point. In embodimentsof the present invention, calculation of a desired turn path shape maybe based upon the turn radius of mobile machine 105. This is done usingstandard mathematical methods for determining the solution of a curve ofknown general formula passing through two known points.

At step 307, the system generates a path plan which follows the firstplanned path until it reaches the first point, then follows the curvegenerated at step 306 until it reaches the second point, then followsthe second planned path.

At step 308 the path plan is output to a known auto-steer system ordriver assistance interface as described in detail above. It is notedthat embodiments of the present invention may be utilized to plan pathsbetween adjacent paths (e.g., paths 401 and 402 of FIG. 4), or betweennon-adjacent paths (e.g., 501 and 503 of FIG. 5) depending upon usersupplied parameters, or other parameters such as the turning radius ofmobile machine 105. It is further noted that system 100 may be used toautomatically steer mobile machine 105 along the plotted paths. Forexample, guidance system 120 may generate steering commands which causemobile machine 105 to follow paths (e.g., 407, 408, and 411 of FIG. 4)without necessitating user intervention.

EXAMPLE 1

Referring now to FIG. 4, system 100 is adapted to plan the turns betweenadjacent swaths along which an agricultural vehicle equipped with system100 will traverse when, for example, plowing an agricultural field.

Referring to step 301 of FIG. 3 above, system 100 accesses a series ofplanned paths 401 to 404. As shown in FIG. 4, planned paths 401-404comprise parallel paths. However, embodiments of the present inventionare not limited to parallel paths alone. Additionally, the pathsaccessed by system 100 may comprise concentric contours or circles, aracecourse pattern, a headland pattern, or a combination thereof.

Referring to 302 of FIG. 3 above, the paths are assigned a sequentialorder. For example, path 401 will be the first path traveled, followedsequentially by paths 402, 403 and 404.

Referring to 303 of FIG. 3, a keyhole shape is selected as the desiredturn path shape. In embodiments of the present invention, the generalequation of the keyhole shape may be (x−a)²+(y−b)²−r²=0, where x and yare Cartesian coordinates and r is the radius of the circle with centreat coordinates (a, b).

Referring to 304 of FIG. 3 above, a first point 405 near the end offirst planned path 401 is determined.

Referring to 305 of FIG. 3, system 100 determines a second point 406 onsecond planned path 402. In one embodiment, system 100 uses standardmathematical techniques to determine the location of point 406, which isthe point on second planned path 402 which lies closest to first point405.

Referring to 306 of FIG. 3, system 100 uses standard mathematicaltechniques to calculate a curve 407 of the desired path shape, whichpasses through both first point 405 and second point 406.

The system may repeat steps 304 to 306 using planned path 402 as thefirst planned path and planned path 403 as the second projected path togenerate curve 408 between points 409 and 410, and again using plannedpath 403 as the first planned path and planned path 404 as the secondplanned path to generate curve 411 between points 412 and 413.

Referring to 307 of FIG. 3, system 100 generates a path plan whichfollows planned path 401 until it reaches point 405, then follows curve407 until it reaches point 406, follows planned path 402 until itreaches point 409, then follows curve 408 until it reaches point 410,follows planned path 403 until it reaches point 412, then follows curve411 until it reaches point 413, then follows planned path 404.

Referring to 308 of FIG. 3, the path plan generated in step 307 is usedby vehicle guidance system 120 to guide mobile machine 105 along theplotted paths.

EXAMPLE 2

Referring now to FIG. 5, system 100 is adapted to plan the turns betweennon-adjacent swaths along which an agricultural vehicle equipped withsystem 100 will traverse when, for example, plowing an agriculturalfield.

Referring again to step 301 of FIG. 3, system 100 accesses a series ofplanned paths 501 to 504.

Referring again to 302 of FIG. 3, the paths are assigned a sequence,i.e. 501, 503, 504, 502.

Referring again to step 303 of FIG. 3, a half ellipse is selected as thedesired turn path shape. The general equation of the ellipse may beb²(x−h)²+a²(y−k)²−a²b²=0, where x and y are Cartesian coordinates, anda, b, h and k are constants.

Referring again to step 304 of FIG. 3, a first point 505 near the end offirst planned path 501 is determined.

Referring again to step 305 of FIG. 3, system 100 uses standardmathematical techniques to determine the location of a second point 506,which is the point on second planned path 503 which lies closest tofirst point 505.

Referring again to step 306 of FIG. 3, system 100 uses standardmathematical techniques to calculate a curve 507 of the desired pathshape, which passes through both first point 505 and second point 506.

The system may repeat steps 304 to 306 using planned path 503 as thefirst planned path and planned path 504 as the second planned path togenerate curve 508 between points 509 and 510, and again using plannedpath 504 as the first planned path and planned path 502 as the secondplanned path to generate curve 511 between points 512 and 513.

At step 307, the system generates a path plan which follows planned path501 until it reaches point 505, then follows curve 507 until it reachespoint 506, follows planned path 503 until it reaches point 509, thenfollows curve 508 until it reaches point 510, follows planned path 504until it reaches point 512, then follows curve 511 until it reachespoint 513, then follows planned path 502.

Referring again to step 308 of FIG. 3, the path plan generated in step307 is used by vehicle guidance system 120 to guide mobile machine 105along the plotted paths.

FIG. 6 is a flowchart of a method 600 for planning the path of anagricultural vehicle in accordance with embodiments of the presentinvention. In step 610 of FIG. 6, a first point of a first planned pathis determined. As described above with reference to FIG. 3, embodimentsof the present invention can access a planned path and determine a firstpoint of the planned path at which an agricultural vehicle will beturned.

In step 620 of FIG. 6, a second point of a second planned path isdetermined. As described with reference to FIG. 3, embodiments of thepresent invention may also access a second planned path and determine asecond point of the second planned path to which the agriculturalvehicle will be turned.

In step 630 of FIG. 6, a path plan connecting the first point and thesecond point is automatically generated. As described above withreference to FIG. 2A and FIG. 3, control component 210 can generate apath plan which connects the first point and the second point. In oneembodiment, the generated path plan can be used by a vehicle guidancesystem to automatically steer the agricultural vehicle along the pathplan without necessitating user input. In another embodiment, the path,or a deviation therefrom, may be displayed, thus permitting an operatorof the agricultural vehicle to steer the vehicle along the path plan.

It should be noted that the descriptions given above are illustrativeonly, and do not restrict the scope of this invention, which is intendedto include such modifications and variations as may be apparent to oneskilled in the art. The preferred embodiment of the present invention, amethod and system for planning the path of an agricultural vehicle, isthus described. While the present invention has been described inparticular embodiments, it should be appreciated that the presentinvention should not be construed as limited by such embodiments, butrather construed according to the following claims.

1. A method for planning a path for an agricultural vehicle comprising a steering mechanism configured to automatically steer the agricultural vehicle, the method comprising: accessing a recorded path plan, the recorded path plan comprising navigation data recorded during a previous path passage of the agricultural vehicle through a work area using a position determining system; determining a first point on a first planned path accessed from the recorded path plan; determining a second point on a second planned path accessed from the recorded path plan; generating a connection path plan connecting the first point and the second point; generating a steering command based on the connection path plan; and providing the steering command to the steering mechanism to cause the agricultural vehicle to travel according to the connection path plan.
 2. The method as recited in claim 1 further comprising: assigning a sequence to the first planned path and the second planned path; and selecting a path shape for connecting the first point and the second point in the connection path plan.
 3. The method as recited in claim 1 wherein generating the connection path plan comprises selecting a path shape for connecting the first point and the second point from the group consisting of a semi-circle and a keyhole.
 4. The method as recited in claim 1 further comprising: determining a first geographic position of the first point and a second geographic position of the second point using the position determining system.
 5. The method as recited in claim 4, wherein: the position determining system is selected from the group consisting of a Global Navigation Satellite System (GNSS) and a terrestrial-based position determining system.
 6. The method as recited in claim 4 further comprising displaying a deviation from the connection path plan on a display device.
 7. The method as recited in claim 1 wherein the navigation data comprises roll, pitch, and yaw data.
 8. A system for planning a path for an agricultural vehicle, the system comprising: an accessor configured for accessing a recorded path plan, the recorded path plan comprising navigation data recorded during a previous path passage of the agricultural vehicle through a work area using a position determining system; a steering controller communicatively coupled to a steering mechanism configured to automatically steer the agricultural vehicle; and a guidance system configured for generating a connection path plan connecting a first point on a first planned path accessed from the recorded path plan and a second point on a second planned path accessed from the recorded path plan using the navigation data, wherein the steering controller is configured to generate a steering command based on the connection path plan and to output the steering command to the steering mechanism to cause the agricultural vehicle to travel according to the connection path plan.
 9. The system of claim 8 wherein the guidance system is further configured for assigning a sequence to the first planned path and the second planned path and for selecting a path shape for connecting the first planned path and the second planned path in the connection path plan.
 10. The system of claim 9 wherein the guidance system selects the path shape from the group consisting of a semi-circle and a keyhole.
 11. The system of claim 8 wherein the position determining system is configured to determine a first geographic position of the first point and a second geographic position of the second point.
 12. The system of claim 8 wherein the position determining system is selected from the group consisting of a Global Navigation Satellite System (GNSS) and a terrestrial-based position determining system.
 13. The system of claim 8 wherein the navigation data comprises roll, pitch, and yaw data.
 14. The system of claim 8 further comprising a display device coupled with the guidance system configured to display a deviation of the agricultural vehicle from the connection path plan.
 15. A control component for an agricultural vehicle, the control component comprising: an accessor configured for accessing a recorded path plan which includes at least a first planned path and a second planned path, the recorded path plan comprising navigation data recorded during a previous path passage of the agricultural vehicle through a work area using a position determining system; an output communicatively couplable to a steering controller configured to control a steering mechanism configured to steer the agricultural vehicle; an input communicatively couplable to the position determining system configured to determine a first geographic position corresponding to a first point on the first planned path and a second geographic position corresponding to a second point on the second planned path; and a path plan generator configured for generating a connection path plan connecting the first geographic position and the second geographic position using the navigation data, wherein the steering controller is configured to control the steering mechanism to cause the agricultural vehicle to travel according to the connection path plan.
 16. The control component of claim 15 wherein the path plan generator is further configured to assign a sequence to the first planned path and the second planned path and to select a path shape for connecting the first geographic position and the second geographic position in the connection path plan.
 17. The control component of claim 16 wherein the path plan generator is configured to select the path shape from the group consisting of a semi-circle and a keyhole.
 18. The control component of claim 15 further comprising a display output communicatively couplable to a display device configured to display a deviation of the agricultural vehicle from the connection path plan.
 19. The control component of claim 15 wherein the position determining system is selected from the group consisting of a Global Navigation Satellite System (GNSS) and a terrestrial-based position determining system.
 20. The control component of claim 15 wherein the navigation data comprises roll, pitch, and yaw data. 